[common] kvmfr: add a new frameSerial field to the KVMFRFrame struct

This new field is used so that when a new client connects an already
connected client can identify any repeated frame that is sent and ignore
it.

common/include/common/KVMFR.h

@@ -28,7 +28,7 @@
 #include "types.h"
 
 #define KVMFR_MAGIC   "KVMFR---"
-#define KVMFR_VERSION 12
+#define KVMFR_VERSION 13
 
 #define KVMFR_MAX_DAMAGE_RECTS 64
 
@@ -69,6 +69,7 @@ KVMFRCursor;
 typedef struct KVMFRFrame
 {
   uint32_t        formatVer;          // the frame format version number
+  uint32_t        frameSerial;        // the unique frame number
   FrameType       type;               // the frame data type
   uint32_t        width;              // the frame width
   uint32_t        height;             // the frame height

host/src/app.c

@@ -94,6 +94,7 @@ struct app
   PLGMPMemory    frameMemory[LGMP_Q_FRAME_LEN];
   unsigned int   frameIndex;
   bool           frameValid;
+  uint32_t       frameSerial;
 
   CaptureInterface * iface;
 
@@ -229,6 +230,7 @@ static bool sendFrame(void)
   }
 
   fi->formatVer         = frame.formatVer;
+  fi->frameSerial       = app.frameSerial++;
   fi->width             = frame.width;
   fi->height            = frame.height;
   fi->realHeight        = frame.realHeight;